1. Field of the Invention
The present invention relates to surveillance systems, and, more particularly, to security systems that receive alarm signals from discrete sensors.
2. Description of the Related Art
Surveillance systems, also known as security systems, are known to include security devices, such as motion detectors, door sensors, window sensors, smoke detectors, etc., for monitoring a secured area of space. Most security systems have a range or variety of sensors to which the security system is connected. The manufacturers of the security systems develop sensors specifically for, and to be compatible with, their security systems. These sensors may be either hardwired to the system or may be in communication with the system via a wireless medium.
A class of consumer products has been developed including stand alone devices used to monitor and alert their users or to signal others of various exceptional conditions via an audible sounder. These devices range from battery operated smoke detectors to freezer thaw alarms to heavy equipment back-up warning devices. In every case when required these devices emit a loud, unmistakable sound.
A problem with such stand alone audible devices is that their effectiveness depends upon being heard by a person who can take appropriate action in response thereto. For example, a smoke alarm may sense smoke and emit an audible alarm in response thereto. However, if no person is within hearing distance of the smoke alarm, or if those hearing the alarm are physically unable to respond, then in that instance the smoke alarm is ineffective. A particular problem is that no central office or monitoring center receives notice of alarm conditions sensed by such stand alone audible devices.
What is needed in the art is a security system that can employ off-the-shelf stand alone audible devices in its network of sensors.